Book/Dissertation / PhD Thesis

FZJ-2017-00964

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Ab initio investigation of hybrid molecular-metallic interfaces as a tool to design surface magnetic properties for molecular spintronics

Friedrich, R. (Corresponding author)FZJ*

2016
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-194-1

Please use a persistent id in citations: http://hdl.handle.net/2128/13660

Abstract: Molecular spintronics aims to store and transmit information encoded in the electron spin using single molecular based magnetic units. In this thesis the magnetic properties of hybrid molecular-metallic interfaces are investigated by $\textit{ab initio}$ density functional theory, the most successful electronic structure method over the last decades. Most of the research in molecular spintronics has been devoted to the magnetic properties of the molecular part of the investigated systems. Here a complementary approach is proposed in which hybrid molecular-metallic interfaces are used as a tool to design surface magnetic properties. Firstly, two effects: (i) in-plane magnetic hardening, i. e. the increase of the exchange coupling between the first layer magnetic surface atoms below the molecule and (ii) inter-layer magnetic softening, i. e. the reduction of the exchange coupling between first and secondmagnetic surface layer locally below the molecule, are investigated in detail: 1. The in-plane magnetic hardening effect is tuned through a chemical functionalization process by investigating a series of $\pi$-bonded molecules adsorbed onto 1 monolayer Fe/W(110) that give rise to specifically tailored magnetic hysteresis curves. 2. The inter-layer magnetic softening effect is generally connected to amolecular induced skyhookmechanism as shown for dioxan and dioxin adsorbed onto 1 and 2 monolayers Fe/W(110): The first layer magnetic atoms belowthe molecule are locally detached from the second layer due to the repulsion of the peripheral hydrogen atoms of themolecule from the surface and the attraction of the central molecular part to the surface. 3. Spatially extended two-dimensional $\pi$-electron systems as graphene and hexagonal boron nitride lead to an in-plane magnetic hardening on Co(111) but do not cause the inter-layer softening revealing that the skyhook mechanism occurs only for finite-size molecular adsorbates. 4. A molecule made up of different rings as triphenyl-triazine can induce multiple intramolecular magnetic units on 2 monolayers Fe/W(110) within a single molecule-surface hybrid system offering prospects for molecular based spin logic devices. In the following it is demonstrated that the concept of molecular induced manipulation of surface magnetic properties can be generalized to surface Rashba systems: [...]

Note: RWTH Aachen, Diss., 2016

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (PGI-1)
2. Quanten-Theorie der Materialien (IAS-1)
3. JARA-FIT (JARA-FIT)
4. JARA - HPC (JARA-HPC)

Research Program(s):

1. 142 - Controlling Spin-Based Phenomena (POF3-142) (POF3-142)
2. 143 - Controlling Configuration-Based Phenomena (POF3-143) (POF3-143)

Appears in the scientific report 2016

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